Delustered cellulosic product and method of preparing same



Patented Feb. 9, 1937 DELUSTERED CELLULOSIC PRODUCT METHOD OF PREPARING SAME Ebenezer Emmet Reid, Baltimore, Md., asslgnor, by mesne assignments, to E. I. du Pont de Nemours & Company, Wilmington, lDeL, a corporation of Delaware No Drawing. Application September 15,1934,

Serial No. 744,266 12 01. (on. 106-40) This invention relates to cellulosic structures such as filaments, threads, fabrics, sheets, films, caps, tubing, or the like. More particularly, this invention relates to cellulosic structures of the type just mentioned having a subdued or low luster and/or that are more or less opaque. v

In the ordinary methods of preparing cellulosic structures, such as filaments, threads, films, caps, tubing, etc.,' from viscose, cuprammonium, nitrocellulose cellulose acetates and other cellulosic solutions (without the addition of opaquing and/or low luster-inducing agents to the" solutions), the products aretransparent or translucent and/or very highly lustrous. For many purposes, transparency, brilliant sheen and luster are not desirable and thus restrict the uses of the materials. Recently, various methods have been proposed for producing cellulosic structures having a low or subdued luster and/or opacity.

I have found that I can produce cellulosic structures characterized by a low luster and/or opacity by incorporating therein a highly insoluble, dimcultly saponifiable metallic salt of an organic acid of the character described in detailhereinafter which imparts opacity and/or low luster by remaining in the cellulosic structure.

An object of the invention comprises the production of new opacified and/ or low luster cellulosic structures A further object of the invention relates to the production of novel cellulosic structures containing organic compounds which remain in the finished article and'which impart opacity and/or low luster. Other objects of the invention will appear hereinafter.

The objects of the invention are accomplished in general by incorporating in the cellulosic solution from which the structure is to be produced an opaquing and/or a low luster-inducing agent of the type'hereinafter more fully described.

' The opaquing and/or low luster-inducing agent contemplated by the ,invention is a highly insoluble, dimcultly saponifiable metallic salt of a carbocyclic or heterocyclic acid highly deficient in hydrogen and which has a refractive index at least 0.1 above that of the cellulosicmedium in which it is to be used. The acid group maybe a carboxylic, thiocarbowlic, sulionic or phosphonic acid group capable of yielding hydrogen ions, providing only that their metallic salts are V substantially insoluble, stable and white.

80 far'as the instant invention is concerned,-

each closed chain of carbon or heteroatoms or combination of carbon and heteroatoms will thalene and carbazole have one, two and three nuclei respectively.

These opaquing and/or low luster inducing agents, which are preferably white in color, possess a sumciently low vapor pressure and are suficiently inert to resist the change or removal from the cellulosic structure in the ordinary process of making and finishing the same during-the manufacture thereof. They also e'flectively re sist removal or change during any of the usual processes to whichthe finished cellulosic structure may be subjected, such as boiling-oil, dye ing, bleaching, washing, ironing, etc. These substances are incompatible with the mass of the substance constituting the final product. They may be soluble, but, in the preferred embodiment of this invention, they are insoluble in thesolution from-which the structure is prepared.

Highly effective delusterants function in' particular by reason of their opacifying power which is a function of the difierence in refractive in- Y have several indexes and the statement just made refers to the highest index of the compound or to any one of the several indexes.

. .As illustrative examples of salts of cyclicorganic acids coming within the scope oi the present invention are the following: The barium or. lead salt of rnumne an coon coon

The silver salt of p'Benzoyl bensoie-scid The barium salt of 2,3, Dibenzoyl amino propionic acid The barium or calcium salt of Benzoyl-p-amino-benzoic acid The barium or calcium salt of Beta naphthoyl-pamino benzoic acid we O-NH-OCOOH The lead salts of:

Phthalamic acid C O 0 H,

N-Phenyl phthalamic acid NH-C O HO 0 C N-elplia-naphtbyl phthalamic acid ran-00 in nooo N -Diphcnylene phthalamic acid and do coon The calcium salt of Benzoyl p'amino benzene sulionic acid The calcium salt of 3,4, li 'lrichloro benzoic acid The barium salt of p-Phenyl bcnzoic acid the opaquing and luster desired in the final product. Cellulosic structures containing these low luster-inducing and/or opaquing agents in amounts ranging from 0.10 to 20.0% by weight have given satisfactory results, but, of course, it is obvious that smaller or larger quantities may be employed as desired. When a viscose solution is employed, satisfactory results may be secured if it contains 7% cellulose and from 0.01 to 1.5% more or less of the low luster-inducing and/or opaquing agent.

If desired, the low luster-inducing agents contemplated by the instant invention may be used in combination with each other and/or with other low luster-inducing agents such as mineral oil, petroleum jelly, waxes, parafiin, benzene, toluene, pine oil or inorganic pigments such as titanium oxide, lithophone, zinc sulfide, etc.

The low luster-inducing agent may be added to the solution at any stage in the course of the manufacture thereof, or after the preparation of the solution and prior to the spinning, extrusion or casting operation. It may be added directly, if the particle size is satisfactory, or after suitable adjustment of the particle size by any of the well known methods such as emulsification, grinding in a colloid mill or pebble mill, or in the form of a suspension or emulsion prepared with or without the assistance of suitable dispersing agents or protective colloids, such as soaps, sulfonated oils, alkyl naphthalene sulfonates, sodium caseinate, etc., or combinations thereof.

In order to more fully explain the principles of this invention, the following illustrative examples are given:

Example I.-'I'he lead salt of N-phenyl phthalamic acid is precipitated in a finely divided form by adding a solution of lead acetate to a solution of the ammonium salt of N-phenyl phthale amic acid. The precipitate is filtered off and dried. The finely divided salt is then dispersed by grinding in a pebble mill with an equal quantity of 2% cellulose acetate dissolved in acetone. The resulting dispersion is incorporated in a 24% cellulose acetate solution in such proportion that 1 part of the lead salt is present for each 10 parts of cellulose acetate. The resulting cellulose acetate solution is dry spun in the usual manner to produce cellulose acetate rayon. The product has a desirable opacity and low luster.

Example II.--'I'he barium salt of benzoyl-p-- aminobenzoic acid is ground in an equal weight of acetone in a pebble mill until all the particles have been reduced to about 4 microns or less in diameter. The resulting dispersion is used in making up cellulose acetate solution for dry spinning in the manner described in Example I.

It is spun in the usual manner and is found to have a desirable opacity and low luster.

Example III .--A sample of viscose rayon is impregnated with 15 parts of a 20% solution of lead acetate for a period of 1 hour. The rayon is then centrifuged and finally immersed in a saturated solution of phthalic acid at -90 C. Lead phthalate is precipitated within the rayon. It is thoroughly washed and dried and is found to have'a desirable opacity and low luster.

It is to be understood that these examples do not in any way restrict the invention thereto but merely illustrate several specific and preferred embodiments which have given satisfactory results.

Though the preferred embodiments of this invention contemplate the incorporation of the time prior-tothe extrusion or casting thereof, satisfactory results may be secured also by applying the low luster-inducing agent to a pre-' viously formed cellulosic structure as for example in the manner describedin Example III.

In other words, the low luster-inducing agent I may be incorporated in the final cellulosic structure by an after-treatment.

Though the invention has been specifically described in connection with the cellulose acetate process,'it is obvious that the principles thereof are equally applicable to the viscose, cuprammonium cellulose, cellulose nitrate, and similar processes. It is only necessary that a'suitable choice of organic acid salt be made so that the required refractive index is obtained and that the solubility characteristics thereoi do not interfere.

It has already been pointed out that the low luster-inducing substance must be incompatible with the mass of substance constituting the final product. In addition, in the case of cellulose acetate or nitrate spinning solutions, it is preferable that the low luster-inducing substance be insoluble in the solvent employed. However, resinous materials and certain crystallized substances, soluble in the solvent, precipitate (on the evaporation oi, the solvent) in the cellulose acetate in the form of fine amorphous or crystalline particles suiiiciently small and well distributed to avoidharmful effect onthe' physical properties of the resulting structure. The advantage in such cases lies in avoiding the necessity for emulsifying or grinding the compounds to obtain suitable subdivision. Suitable compounds may be readily selected from any specific system by one skilled. in the art.

While the invention has been described generally with respect to the use of the various compounds mentioned herein the op 1, cel-,

lulosic structures prepared by casting and/or spinningmethods, it is desired to emphasize the fact that these compounds are of special benefit in the spinning of artificial silk. Thus, undelustered artificial silk has a shade and luster.

* which is undesired fora great many purposes.

In accordance with the presentinvention, it is possible to produce artificial silk, particularly of the regenerated cellulose type prepared'irom viscose or cuprammonium cellulose, having a pleasing dull appearance, the dullness being of any degree desired, in which the opaquing and/or. delustering agent is uniformly distributed'and which does not interfere with the tenacity of the yarn to any large extent.

Since itis obvious that various changes and modifications may be made in the above description without departing from the nature or spirit thereof, this invention is not restricted thereto except as set forth in the claims.

I claim: i

1. Artificial cellulosic films, filaments and the like, containing an incompatible, finely divided opacifying and/or delusterlng agent comprising a solt of a polyvalent metal and an acid of the group consisting of benzoyl p-aminobenzoic acid, naphthol p-aminobenzoic acid, phthalic acid, phthalamic acid and n-lphenyl phthalamic acid.

like, containing an incompatible finely divided opacifyingand/or delustering agent comprising a a salt of a polyvalent metal and benzoyl-p-aminobenzoic acid.

4. Artificial cellulosic films, filaments and the like, containing an-incompatible, finely divided" opacifying and/or delustering agent comprising a salt of a polyvalent metal and phthalic acid.

5. 'An artificial thread comprising-a cellulosic material having opacity and/or low luster imparted thereto by the incorporation therein of an incompatible, finely divided substance comprising a salt of a polyvalent metal and an acid of the group consisting of benzoyl p-aminobenzoic acid, naphthoyl p-aminoberlzoic acid. phthalic acid, phthalamic acid and. n-phenyl phthalamic acid.

6. An artificial thread comprising a cellulosic material having opacity and/orlow luster imparted thereto by the incorporation therein of an incompatible, finely divided substance comprising a salt of a polyvalent metal and n-phenylphthalamic acid.

'7. An artificial thread comprising a cellulosic material having opacity and/or low'luster imparted thereto by the incorporation therein of an incompatible, finely dividedsubstance comprising a salt of a polyvalent metal and 'benzoyl-paminobenzoic acid.

8. An artificial thread comprising a cellulosic material having opacity and/or low luster imparted thereto by the incorporation therein of an incompatible, finely divided substance comprising a salt of a polyvalent metal and phthalic acid. 9. Artificial cellulosic films, filaments, and the like, containing an incompatible, finely divided opacifying and/or delusterlng agent comprising a highly insoluble and dimcultly saponifiable, colorless salt of a metal and an aromatic acid having at least one cyclic nucleus highly deficient in hydrogen. v

10. Artificial cellulosic films, filaments, and the like, containing an incompatible, finely divided opacifying and/or delustering agent comprising a highly insoluble and dificultly saponiflable salt of a polyvalent metal and an aromatic acid, said salt having an index of refraction diflering by at least 0.1 from the index of refraction of the cellulosic medium.

11. An artificial thread comprisng a cellulosic material having opacity and/or low luster imparted thereto by incorporation therein of an incompatible, finely divided substance comprising a highly insoluble and difilcultly saponifiable salt.

12. The articles defined in claim locharacterized in that saidsalt is colorless.

CERTIFICATE OF CORRECTION.

Patent No. 2,069,773. February 9, 1937.

EBENEZER EMMET REID.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 10, after the word "nitrocellulose insert a comma; page 5, first column, line 67, claim 1, for "naphthol" read naphthoyl; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Gffice.

Signed. and sealed this 27th day of April, A. D. 1937.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

